In the packaging of integrated circuits, semiconductor dies may be stacked through bonding, and may be bonded to other package components such as interposers and package substrates. The resulting packages are known as Three-Dimensional Integrated Circuits (3DICs). Heat dissipation is a challenge in the 3DICs.
A bottleneck may exist in efficiently dissipating the heat generated in the inner dies of the 3DICs. In a typical 3DIC, the heat generated in inner dies may have to be dissipated to outer components before the heat can be conducted to a heat spreader. Between the stacked dies and outer components, however, there exist other materials such as underfill, molding compound, and the like, which are not effective in conducting heat. As a result, the heat may be trapped in an inner region of a bottom stacked die and cause a sharp local temperature peak (sometimes referred to as a hot spot). Furthermore, hot spots due to heat generated by high-power consuming dies may cause thermal crosstalk problems for surrounding dies, negatively affecting the surrounding dies' performance and the reliability of the whole 3DIC package.